Air-brake.



Patented Aug. 8, I899. W. B. MANN.

AIR BRAKE.

Application filed July 28, 1898.)

2 Sheets-Sheet I.

(No Model.)

Rs co. monxuma, wAsNmcYon n c No. 630,376. Patented Aug. 8, I899.

w. B. MANN.

AIR BRAKE.

(Application filed July 28, 1898.\

2 Sheets-Sheet 2.

mow-

' fiavewzdr.

(No Model.)

UNITED STATE PATENT OFFICE.

WILLIAM B. MANN, OF BALTIMO RE, MARYLAND.

AIR-BRAKE.

s'P'EcIrIoATIoN formingpart of Letters Patent No. 630,376, dated August 8, 1899. Application filed July 28, 1898. Serial No. 686,721. (No model.)

To all whom it may concern:

Be it known that I,-WILLIAM B. MANN, of Baltimore, Maryland, have invented a new and useful Improvement in Air-Brakes,which improvement is fully set forth in the following specification.

My invention relates to that class of fluidpressure brakes known as. quick-action? brakes, in which the action of all the brakes on a long train is so nearly simultaneous that injurious shocks are avoided between the several cars forming the train. g

It has been demonstrated that in order to obtain the required rapidity of action of the brakes on a long train of cars it is necessary to reduce the fluid-pressure in the train-pipe with greater celerity than would be done by venting such pipe at the engineers valve alone, and the train-pipe is therefore vented serially at several points along the train, preferably under each car. In thus serially vent ing the train-pipe with a View to rapidly reducin g the pressure therein as the initial step in securing the desired quick application of the brakes the air from the train-pipe has been allowed to escape to the atmosphere or has been conducted into the brake-cylinder, the former method having the advantage of being more rapid.

The object of the present invention is to provide means acting in combination with the triple valve whereby the train-pipe may be serially and rapidly vented to the atmosphere when it is desired to greatly reduce the pressure in the pipe to apply the brakes in an emergency, but which will remain inactive when it is desired to but slightly reduce the pressure in the train-pipe for ordinary service applications of the brakes.

Nith this object in view myinvention consists of a triple valve constructed to admit compressed air from the auxiliary reservoir to the brake-cylinder for both service and emergency applications of the brakes, combined with a venting or exhaust valve controlling communication between the trainpipe and the, atmosphere, said valve being held to its seat at all times except when the triple valve is thrownin anemergency application of the brakes, when the exhaust or venting valve instantly opens and upon the train-pipe pressure being reduced to the detrain-pipe.

gree desired at once closes without regard to the then position of the triple valve. In or der that the exhaust-valve may thus act, I provide means whereby it is held to its seat by pressure equal to ordinary train-pipe pressure when the brakes are off, means whereby a column of air at a pressure exceeding trainpipe pressure is applied to open the exhaustvalve when the triple valve is thrown to emergency position, and means whereby the pressure of said column of air may be quickly reduced and the exhaust-valve closed before the return movement of the triple valve.

In the preferred construction the exhaustvalve is of the puppet form and is held to its seat by train-pipe air in a chamber or cylinder behind the valve, which chamber communicates through a restricted passage with the Upon the movement of the triple valve for an emergency application of the brakes a plunger attached to the motor-piss ton of the triple valve acts to compress a column of air to a degree exceeding train-pipe pressure, and this column of air acting on the exhaust-valve opens it and holds it open until the pressure of said column of air is reduced (by a leak or exhaust provided for that purpose) to a point Where it is overcome by the pressure in the closing chamber, when the exhaust-valve is promptly closed by the pressure in said chamber.

I have illustrated in the accompanying drawings one form which my invention may assume, in which- Figure 1 is a vertical longitudinal section of a triple valve, venting-valve, and cooperating parts, together with the valve-casing, showing the conduits leading therefrom to the train-pipe, the auxiliary reservoir, the brake-cylinder, and the atmosphere, parts being shown in elevation and the valves in the position which they occupy when the brakes are released. Fig.2 is a view similar to Fig. 1 with the, parts in thepositionthey occupy when thebrakes are being applied for service stops. Fig. 3 is a view similar to Fig. 1 with the parts in the positionthey occupy when the brakesare being applied foremergency stops: Fig. 4 is a like view with the parts in the position they assume immediately after the train-pipe has been vented in making an emergency stop and while the brakes i'sh'oivh in Fig. 3.

of triplevalve operated by the partial andI full traverse of a motor-piston for making service and emergency application of the brakes; but I have shown it, for purposes of 5 illustration only, as used in connection with a triple valve of the general character-of that shown in United States Patent No. 220,556.,

Referringto the drawings, a valve-casing is formed by uniting in anyapproved way the two castings A A.

B is the triple-valve chamber, 0 the pistoneh-ahlber, and D the main valve, having, the service and graduating passaged and the exhaiist-passage d.

E is the motor-piston, e the piston-stem, and E the valve-operating head connected tnereta'whner is the passage leading to the train-pipe; G,-t'he passage to the auxiliary reser'voir'; H; the passage to the brake-cylinder, and I the vent-passage leading to the atmoseer-e. tween the brake-cylinder-an'd the atmosphere through. passage H,- port 7t, passage (1, port i, and passage 1, while at the same time compressed air from the train-pipe enters through the passages F f, 'chambe'r O, feed-in valve 0, valve-chamber B, and assage G to the auxiliary reservoir. In service application of the brakes (see Fig. 2) ports h and 11 are disconirected and air passes from the auxiliary reservoir through passages Gr, valve chamber B, restricted passage (1 in main valve D, port h, and passage H to the brakeeylinder, while in emergencyapplication (see Fig. 3) the air asses from the auxiliary reservoir through assages, port h, and passage H to the brakeeyli'rrder.

owing to the lost motion between the pisten-stein head E and the main valve D, the power in the brake-cylinder during service applications may he graduated through the 'aetion of the graduating-valve K, which controls the port leading into the restricted passage d from the valve-chamber 13.

Opening set f-I'O'lii the piston-chamber'O and on 'thes-idetlreredf opposite the triple-valve chamber Bis a port M,'which leads into a theater Y, which chamber has direct cominhnication to the atmosphere through the passage 1 l n'the chamber Y andopposite the port a cylinder W, wit-11in which a piston V snugly 'fit's.

with-the shoulder 10, which limits the throw Communication is established be-,v

As shown, this cylinder \Vis j edin a screw-cap attached to and pro-i ctin-g within the chamber Y and formed,

which surrounds the hollow stem and normally seats upon and closes the port M. The interior diameter of the hollow piston-stem V is considerably less than the port M, and a plunger E attached to the piston E, passes through the port M and enters the hollow sternV the fit of the plunger'E in the hollow stem V being such that air may pass into or out of the hollow stem around the plunger E The cylinder W behind the piston 'V is in communication with the train-pipe through 1 the restricted passage to, formed in the walls of the chamber Y. The air passing through this passage-w is adjustably controlled by the screw-plug w, having a conical point extending into the passage, so that the area of the passage at this point may be regulated by turning the nut.

The operation of the device is as follows: When in service application of the brakes the train-pipe pressure is slightly reduced and the piston E m akes a partial traverse and takes the position-shown in Fig.2, the plunger E enters the hollow stem V and slightly compresses the air in said hollow-stem; but by reason of the loose fit of the plunger in the hollow stem the air in the latter escapes into the chamber 'Owithout any movement being imparted to the piston V, and consequently the valve V remains seated. When, however, the pressure in the train-pipeissuddenly and considerably reduced and in consequence the piston E makes its full traverse and takes the position shown in Fig. 3, the plunger E enters the hollow ste-mV to such an extent that the air in the stem V is greatly compressed, and this air so compressed reacts against the closed end of the stem and forces the piston V into the position shown in Fig. 3, thereby raising the valve V off its seat and opening the port M. The air in the t'rainpipe then escapes to the atmosphere through the passages F f, chamber 0, port M, chamber Y, and port y. Because o f-the loose fit of the plunger E in the hollow stem V the compressed air in "the hollow stem escapes morera'pidl y from behind the plunger E than does the air in "the cylinder 'W from behind the piston V, and as 'soon as the pressure in front of the piston V is overcome by that in the cylinder W the piston V, piston-stem V and valve V will be moved from'th'e opener venting position(shown in Fig. 3) to'th'e closed position of Fig. 4. When compressed air is again admitted to the train-pipe, the val-veis held in its closed position by reason of the fact that the area of the piston V-eX-posed'to pressure in the cylinder W and which tends to hold the valve closed is greater than that 'tio'n between-the valve V and the piston E and'that the valve maybe and is closed when the piston is in its normal position, Fig. 1, in

; which is exposed to a like pressure from the or the piston V and provides a cushioning: space W even when the valve V and "piston V are in their rearmost position, as '1 The piston V has a hol-Z 16w stem VZ'tvhic'h is closed at the end where} the piston isa ttached and open at its otherl "end and which bears an annular valve V,

position of partial traverse, Fig. 2, or in position of full or final traverse, Fig. 4.

By properly proportioning the port y and the restricted passage w by use of plug 10 and the escape of air between the plunger E and hollow stem V the valve V may be caused to close when the train-pipe is fully exhausted to the atmosphere or at any other particular degree of exhaust that may be desired.

It will be understood that my invention is not limited to the precise details of construction herein shown and described and that the invention may find various mechanical expressions without departing from the fundamental inventive idea.

Having thus described my invention, what I claim is- 1. The combination of a train-pipe, an auxiliary reservoir, a brakecylinder, a triple valve and a piston having a partial and full traverse for operating the same, with an exhaust-valve closing a port leading from the train-pipe to the atmosphere, means whereby said exhaust-valve is held to its seat by trainpipe pressure, means whereby a column of air exceeding train-pipe pressure is applied to open the exhaust-valve when the triple valve is thrown to emergency position, and means whereby the pressure of said column of air is quickly reduced and the exhaust valve closed, substantially as described.

2. The combination of a train-pipe, an auxiliary reservoir, a brakewylinder, a triple valve and its operating-piston, with a valve closing a port between the train-pipe and the atmosphere, a difierential piston normally holding said valve seated and means increasing the air-pressure on the smaller side of said differential piston when the triple valve is thrown to its emergency position, substantially as described.

3. The combination of the train-pipe, auxiliary reservoir, brake-cylinder, triple valve and operating-piston therefor with the exhaust-valve, the differential piston attached thereto and normally exposed to train-pipe pressure on both sides, and means for increasing the pressure on one side of said diiferential piston to a point above train-pipe pressure, whereby the differential piston is actuated to open the exhaust-valve, substantially as described.

4. The combination of the train-pipe, auxiliary reservoir, brake-cylinder, triple valve and operating-piston therefor, with the exhaust-valve, the differential piston attached thereto and normally exposed to train-pipe pressure on'both sides, means actuated on the emergency throw of the triple-valve piston to increase the pressure on one side of said differential piston to a point above train-pipe pressu re,whereby the exhaust-valve is opened and means reversing the preponderance of pressure whereby the exhaust-valve is closed, substantially as described.

5. The combination with the train-pipe, auxiliary reservoir, brakecylinder, triple valve and its operating-piston, of a valve controlling a port leading from the train-pipe to the atmosphere and normally held seated by the train-pipe pressure, and means for securing air-pressure exceeding and overcoming said train pipe pressure and opening said valve when the triple valve is thrown to its emergency position, substantially as described.

6. The combination with the train-pipe,the auxiliary reservoir, the brake-cylinder, the triple valve and its operating-piston, of a valve controlling a port leading from the train-pipe to the atmosphere, a differential piston \normally holding said valve seated against train-pipe pressure and means for increasing the air-pressure on the train-pipe side of said piston and opening said valve when the triple valve is thrown to its emergency position, substantially as described.

7. .The combination of the exhaust-valve, the differential piston exposed to air-pressure on both sides and the hollow piston-stem, with the triple-valve piston and the plunger thereon entering said hollow piston-stem, substantially as described.

8. The combination with a cylinder having an open port leading to the atmosphere, a port leading to the train-pipe, a valve closing the same, and a restricted passage connecting said chamber with the train-pipe, of a difierential piston in said cylinder between the open port and the mouth of the restricted passage, a hollow stem connecting said piston and valve and a plunger attached to the triple-valve piston and loosely fitting said hollow stem, substantially as described.

9. The combination of the train-pipe, auxiliary reservoir, brake-cylinder, triple valve and its operating-piston, with an exhaustvalve controlling a port between the trainpipe and the atmosphere, a differential piston attached to said valve, means alternating the preponderance of pressure on the oppo site sides of said differential piston whereby the exhaust-valve is opened and closed, and adjustable means regulating the length of time during which said exhaust-valve remains open, substantially as described.

In testimony whereof I have signed this specification in the presence of two subscribing witnesses.

\VILLIAM B. MANN.

lVitnesses:

S. T. CAMERON, REEVE LEwIs. 

